5-ht3 receptor antagonists

ABSTRACT

The present invention provides 5-HT3 receptor antagonists of Formula (I): 
     
       
         
         
             
             
         
       
     
     which are useful for the treatment of diseases treatable by inhibition of 5-HT3 receptor such as emesis, pain, drug addiction, neurodegenerative and psychiatric disorders, and GI disorders. Also provided are pharmaceutical compositions containing such compounds and processes for preparing such compounds.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/672,709, filed Jul. 17, 2012, and U.S. Provisional Application No.61/708,521, filed Oct. 1, 2012, which are herein incorporated byreference.

FIELD OF INVENTION

The present invention provides compounds that are 5-HT3 receptorantagonists and are therefore useful for the treatment of diseasestreatable by inhibition of the 5-HT3 receptor such as emesis, pain, drugaddiction, neurodegenerative and psychiatric disorders, and GIdisorders. Also provided are pharmaceutical compositions containing suchcompounds and processes for preparing such compounds.

BACKGROUND

Serotonin type 3 (5-HT3) receptors are part of the serotonergic system.Unlike other receptors of this system, which are all G-protein coupledreceptors, the 5-HT3 receptors are ligand-gated ion channels and belongsto the superfamily of Cys-loop receptors that include nicotinicacetylcholine, γ-aminobutyric acid (GABA)A and glycine receptors and aZn+2 activated cation channel (see Davies et al., 2003, J. Biol. Chem.,278, 712-717; Connolly et al., 2004, Biochem Soc Trans 32, 529-534). The5-HT₃ receptors are made up of 5 subunits arranged around a central ionconducting pore, which is permeable to sodium, potassium, and calciumions (see Boess et al., 1995, J. Neurochem. 64, 1401-1405; Connolly etal., 2004, Biochem Soc Trans 32, 529-534). Binding of serotonin to the5-HT₃ receptors opens the channel, which, in turn, leads to anexcitatory response in neurons. Functional data reported for 5-HT3receptors refer to 5-HT3A or 5-HT3AB receptors since the properties ofthese receptor subtypes have been most extensively studies to date.

5-HT3 receptors are known to be expressed in the central nervous systemin regions involving vomiting reflex, processing of pain, cognition andanxiety control and play a role in the pathogenesis of diseases such asemesis, migraine, drug addiction, and neurodegenerative and psychiatricdisorders such as anxiety and depression (see Hewlett et al., 2003 J.Clin. Psychiatry 64, 1025-1030; Kelley et al., 2003a, Eur J. Pharmacol.,461, 19-25; Haus et al., 2000 Scand J Rheumatol Suppl 113, 55-58; andFaris et al., 2006 J affect Disorder 92, 79-90), eating disorders(Hammer et al., 1990 Am J Physiol 259, R627-R636, and Jiang & Gietzen1994 Pharmacol Biochem Behav 47, 59-63), schizophrenia (see Hermann etal. 1996 Biochem Biophys Res Commun 225, 957-960; Sirota et al., 2000 AmJ Psychiatry 157, 287-289; Adler et al., 2005 Am J Psychiatry 162,386-388; Koike et al., Levkovitz et al, 2005 Schizophr Res 76, 67-72),cognitive dysfunction associated with schizophrenia (see Zhang et al.,2006 Schizophr Res 88, 102-110; Akhondzadeh et al., 2009 Schizophr Res107, 206-212), congnitive dysfunction associated with Parkinson'sdisease, Huntington's Chorea, presenile dementias and Alzheimer'sdisease (see Costall and Naylor 2004 CNS Neurol Disord 3, 27-37)substance abuse and addiction (see Johnson et al., 2002Psycho-pharmacology (Berl) 160, 408-413; Johnson, 2004 CNS Drugs 18,1105-1118; Dawes et al., 2005 Addict Behav 30, 1630-1637, Johnson 2006Drug Alcohol Depend 84, 256-263), autism spectrum disorders (seeAnderson et al Neurogenetics 10, 209-216) and pain (see Kayser et al,2007 Pain 130, 235; Glaum et al., 1998 Neurosci Lett 95, 313-317;Schworer & Ramadori 1993 Clin Investig 71, 659; Thompson and Lummis 2007Exp Opin Ther Targets, 11, 527-540). In addition, 5-HT3 receptors areexpressed in the GI tract and hence may play a role in GI disorders suchas dyspepsia, gastroesophagal reflux disease and irritable bowelsyndrome (see Graeff 1997 Psychiatr Clin North Am 20, 723; Thompson andLummis 2007 Exp Opin Ther Targets, 11, 527-540; Barnes et al. 2009Neuropharmacology 56, 273). Expression of the 5-HT3A subunit has alsobeen discovered extraneuronally in immune cells such as monocyes,chondrocytes, T-cells, synovial tissue and platelets (Fiebich et al.,2004 Scan J Rheumatol Suppl, 9-11, Stratz et al., 2008 Thromb Haemost99, 784) and of 5-HT3A, C-E within the lamina propia in the epitheliumof the gut mucose (Kapeller et al., J Comp Neuro., 2008; 509: 356-371)thus suggesting they may be involved in immunological and inflammatorydiseases like atherosclerosis, tendomyopathies and fibromyalgia.

The 5-HT3 antagonists currently on the market are approved only for thetreatment of emesis or irritable bowel syndrome. It is desirable todiscover 5-HT3 antagonists that can be used to treat other diseasesamenable to alleviation by 5-HT3 receptors such as schizophrenia andcognitive disorder associated with schizophrenia. The present inventioncan fulfill this and related needs. It is desirable to discover 5-HT3antagonists that have desirable pharmacokinetic and pharmacodynamicproperties, such as selectivity over nicotinic-α7 receptors.

Certain antagonists the 5-HT3 receptor are described in U.S. Pat. No.4,789,763; U.S. Pat. No. 4,803,199; U.S. Pat. No. 4,886,808; U.S. Pat.No. 4,910,193; U.S. Pat. No. 5,334,831; EP 0 469 449; and EP 0 491 664.Certain inhibitors of TGF-β are described in EP 1 156 045 and certaintreatment of nephritis is described in EP1 243 268. Certain antagonistsof 5-HT4 are described in EP 0 708 105. Certain ligands of nicotinic-α7receptors are described in WO 2007/038367. Certain P2X7 antagonists aredisclosed in WO 2009/023623.

SUMMARY

In a first aspect, this invention is directed to a compound of Formula(I):

wherein:Z is O or NR_(a) where R_(a) is hydrogen or C₁₋₆ alkyl;R₁ is a ring of the formula (a)-(h) below:

R₂ is hydrogen, C₁₋₆ alkyl, or C₁₋₆ haloalkyl;each R₃ is independently hydrogen, C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆haloalkoxy, or halo and can be present on any carbon atom in the rings;R₄ is pyridinyl or pyrazolyl each optionally substituted with one or twosubstituents independently selected from C₁₋₆ alkyl, C₁₋₆ haloalkyl,C₁₋₆ haloalkoxy, C₁₋₆ alkoxy, cyano, or halo; all of X₁-X₄ are CR₅ orone of X₁-X₄ is N and the others are CR₅;each R₅ is independently hydrogen, C₁₋₆ alkyl, halo, hydroxy, or cyanoprovided that at least one of R₅ is hydrogen;X⁵ is N or CR⁶ where R⁶ is hydrogen, C₁₋₆ alkyl, or halo;or a pharmaceutically acceptable salt thereof or N-oxide thereof.

In a second aspect, this present invention is directed to apharmaceutical composition comprising a compound of Formula (I) (or anyembodiments thereof disclosed herein) or a pharmaceutically acceptablesalt thereof and a pharmaceutically acceptable excipient.

In a third aspect, this present invention is directed to a method oftreating a disease treatable by administration of a 5-HT3 receptorantagonist which method comprises administrating to the patient apharmaceutical composition comprising a compound of Formula (I) (or anyembodiments thereof disclosed herein) and/or a pharmaceuticallyacceptable salt and a pharmaceutically acceptable excipient. That is,the present invention provides a method of treating a disease treatableby administration of a 5-HT3 receptor antagonist comprising:administrating to a patient in need thereof a therapeutically effectiveamount of a compound of Formula (I) (or any embodiments thereofdisclosed herein) or a pharmaceutically acceptable salt thereof.

In one embodiment of the third aspect, the disease treatable byadministration of a 5-HT3 receptor antagonist is emesis, migraine,substance abuse and addiction, neurodegenerative and psychiatricdisorders such as anxiety and depression, eating disorders,schizophrenia, cognitive dysfunction associated with schizophrenia,Parkinson's disease, Huntington's Chorea, presenile dementias andAlzheimer's disease, and pain; GI disorders such as dyspepsia,gastroesophagal reflux disease, and irritable bowel syndrome; andimmunological disorders and inflammation such as atherosclerosis,tendomyopathies and fibromyalgia. In another embodiment of the thirdaspect the disease treatable by administration of a 5-HT3 receptorantagonist is schizophrenia or cognitive dysfunction associated withschizophrenia.

In a fourth aspect, the compound of Formula (I) (or any embodimentsthereof disclosed herein) or a pharmaceutically acceptable salt thereofis administered in combination with an antipsychotic drug. In oneembodiment of the fourth aspect, the antipsychotic drug is AMG 747,bitopertin (RG1678), RG1578, AMG579, GSK1018921, aripiprazole,risperidone, olanzapine, quetiapine, ziprasidone, or clozapine.

In a fifth aspect, the invention is directed to use of compound ofFormula (I) (or any embodiments thereof disclosed herein) or apharmaceutically acceptable salt thereof as a medicament.

In a sixth aspect, the invention is directed to a compound of Formula(I) (or any embodiments thereof disclosed herein) or a pharmaceuticallyacceptable salt thereof for use to treat a disease treatable byadministration of a 5-HT3 receptor antagonist as disclosed herein.

In one embodiment of the fifth and sixth aspects, the use is for thetreatment of emesis, migraine, substance abuse and addiction,neurodegenerative and psychiatric disorders such as anxiety anddepression, eating disorders, schizophrenia, cognitive dysfunctionassociated with schizophrenia, Parkinson's disease, Huntington's Chorea,presenile dementias and Alzheimer's disease, and pain; GI disorders suchas dyspepsia, gastroesophagal reflux disease, and irritable bowelsyndrome; and immunological disorders and inflammation such asatherosclerosis, tendomyopathies and fibromyalgia. In another embodimentof the fifth and the sixth aspects the use is for the treatment ofschizophrenia or cognitive dysfunction associated with schizophreniaalso known as cognitive impairment associated with schizophrenia. In yetanother embodiment of the fifth and the sixth aspects, and embodimentscontained therein, the compound of Formula (I) is administered incombination with an antipsychotic drug. In one embodiment, theantipsychotic drug is AMG 747, bitopertin (RG1678), RG1578, AMG579,GSK1018921, aripiprazole, risperidone, olanzapine, olanzapinequetiapine, or ziprasidone, clozapine.

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless otherwise stated, the following terms used in the specificationand claims are defined for the purposes of this application and have thefollowing meaning:

“C₁₋₆ alkyl” means a linear saturated monovalent hydrocarbon radical ofone to six carbon atoms or a branched saturated monovalent hydrocarbonradical of three to six carbon atoms, e.g., methyl, ethyl, propyl,2-propyl, butyl (including all isomeric forms), pentyl (including allisomeric forms), and the like.

“C₁₋₆ alkoxy” means a —OR radical where R is C₁₋₆ alkyl as definedabove, e.g., methoxy, ethoxy, propoxy, or 2-propoxy, n-, iso-, ortert-butoxy, and the like.

“C₁₋₆ haloalkyl” means C₁₋₆ alkyl radical as defined above, which issubstituted with one or more halogen atoms, preferably one to fivehalogen atoms, preferably fluorine or chlorine, including thosesubstituted with different halogens, e.g., —CH₂Cl, —CF₃, —CHF₂, —CH₂CF₃,—CF₂CF₃, —CF(CH₃)₂, and the like. When the C₁₋₆ alkyl is substitutedwith only fluoro, it can be referred to in this application as C₁₋₆fluoroalkyl.

“C₁₋₆ haloalkoxy” means a —OR radical where R is C₁₋₆ haloalkyl asdefined above e.g., —OCF₃, —OCHF₂, and the like. When R is haloalkylwhere the C₁₋₆ alkyl is substituted with only fluoro, it can be referredto in this application as C₁₋₆ fluoroalkoxy.

“Halo” means fluoro, chloro, bromo, or iodo, preferably fluoro orchloro.

The present invention also includes the prodrugs of compounds of Formula(I). The term prodrug is intended to represent covalently bondedcarriers, which are capable of releasing the active ingredient ofFormula (I) respectively, when the prodrug is administered to amammalian subject. Release of the active ingredient occurs in vivo.Prodrugs can be prepared by techniques known to one skilled in the art.These techniques generally modify appropriate functional groups in agiven compound. These modified functional groups however regenerateoriginal functional groups in vivo or by routine manipulation. Prodrugsof compounds of Formula (I) include compounds wherein a hydroxy, amino,carboxylic, or a similar group is modified. Examples of prodrugsinclude, but are not limited to esters (e.g., acetate, formate, andbenzoate derivatives), carbamates (e.g., N,N-dimethylaminocarbonyl) ofhydroxy or amino functional groups in compounds of Formula (I)), amides(e.g., trifluoroacetylamino, acetylamino, and the like), and the like.Prodrugs of compounds of Formula (I) are also within the scope of thisinvention.

The present invention also includes protected derivatives of compoundsof Formula (I). For example, when compounds of Formula (I) containgroups such as hydroxy, carboxy, thiol or any group containing anitrogen atom(s), these groups can be protected with a suitableprotecting groups. A comprehensive list of suitable protective groupscan be found in T. W. Greene, Protective Groups in Organic Synthesis,John Wiley & Sons, Inc. (1999), the disclosure of which is incorporatedherein by reference in its entirety. The protected derivatives ofcompounds of Formula (I) can be prepared by methods well known in theart.

A “pharmaceutically acceptable salt” of a compound means a salt that ispharmaceutically acceptable and that possesses the desiredpharmacological activity of the parent compound. Such salts include:acid addition salts, formed with inorganic acids such as hydrochloricacid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, andthe like; or formed with organic acids such as formic acid, acetic acid,propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolicacid, pyruvic acid, lactic acid, malonic acid, succinic acid, malicacid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoicacid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid,methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid,2-hydroxyethanesulfonic acid, benzenesulfonic acid,4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid,4-toluenesulfonic acid, camphorsulfonic acid, glucoheptonic acid,4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionicacid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuricacid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylicacid, stearic acid, muconic acid, and the like; or salts formed when anacidic proton present in the parent compound either is replaced by ametal ion, e.g., an alkali metal ion, an alkaline earth ion, or analuminum ion; or coordinates with an organic base such as ethanolamine,diethanolamine, triethanolamine, tromethamine, N-methylglucamine, andthe like. It is understood that the pharmaceutically acceptable saltsare non-toxic. Additional information on suitable pharmaceuticallyacceptable salts can be found in Remington's Pharmaceutical Sciences,17th ed., Mack Publishing Company, Easton, Pa., 1985, which isincorporated herein by reference.

The compounds of the present invention may have asymmetric centers.Compounds of the present invention containing an asymmetricallysubstituted atom may be isolated in optically active or racemic forms.It is well known in the art how to prepare optically active forms, suchas by resolution of materials. All chiral, diastereomeric, meso, racemicforms are within the scope of this invention, unless the specificstereochemistry or isomeric form is specifically indicated.

Additionally, as used herein the term C₁₋₆ alkyl and terms derivedtherefrom includes all the possible isomeric forms of said C₁₋₆ alkylgroup. Furthermore, the heteroaryl include all the positional isomers.Furthermore, all polymorphic forms and hydrates of a compound of Formula(I) are within the scope of this invention.

The terms “compound” and “a compound of the invention” and “compound ofthe present invention” and the like, and their plural forms include theembodiment of Formula (I) and the other more particular embodimentsencompassed by Formula (I) described herein and exemplified compoundsdescribed herein or a pharmaceutically acceptable salt of each of theseembodiments. All references to compounds, include all isotopes of theatoms contained therein, including isotopically-labeled compounds.

The compounds of the present invention exist as tautomers. Alltautomeric forms the compounds of the invention are contemplated to bewithin the scope of the present invention.

“Optional” or “optionally” means that the subsequently described eventor circumstance may but need not occur, and that the descriptionincludes instances where the event or circumstance occurs and instancesin which it does not.

A “pharmaceutically acceptable carrier or excipient” means a carrier oran excipient that is useful in preparing a pharmaceutical compositionthat is generally safe, non-toxic and neither biologically nor otherwiseundesirable, and includes a carrier or an excipient that is acceptablefor veterinary use as well as human pharmaceutical use. “Apharmaceutically acceptable carrier/excipient” as used in thespecification and claims includes both one and more than one suchexcipient. Pharmaceutically acceptable excipients are well known in theart, such as those in Remington's Pharmaceutical Sciences, 17th ed.,Mack Publishing Company, Easton, Pa., 1985.

The terms “condition,” “disorder,” and “disease” relate to any unhealthyor abnormal state.

“Treat,” “treating,” or “treatment” of a disease includes:

(1) preventing the disease, i.e. causing the clinical symptoms of thedisease not to develop in a mammal that may be exposed to or predisposedto the disease but does not yet experience or display symptoms of thedisease;

(2) inhibiting the disease, i.e., arresting, controlling, slowing,stopping, or reducing the development of the disease or its clinicalsymptoms; or

(3) relieving the disease, i.e., causing regression of the disease orits clinical symptoms or improvement of the disease or its clinicalsymptoms

The terms “treat,” “treating,” and “treatment,” do not necessarilyindicate a total elimination of any or all symptoms or a cure of thedisease.

As used herein the terms “patient” and “subject” includes humans andnon-human animals, for example, mammals, such as mice, rats, guineapigs, dogs, cats, rabbits, cows, horses, sheep, goats, and pigs. Theterm also includes birds, fish, reptiles, amphibians, and the like. Itis understood that a more particular patient is a human. Also, moreparticular patients and subjects are non-human mammals, such as mice,rats, and dogs.

A “therapeutically effective amount” means the amount of a compound ofFormula (I) or a pharmaceutically acceptable salt thereof that, whenadministered in single or multiple doses, to a mammal for treating adisease, is sufficient to effect such treatment for the disease. The“therapeutically effective amount” will vary depending on the compound,the disease and its severity and the age, weight, etc., of the mammal tobe treated, the degree of or involvement or the severity of thecondition, disorder, or disease, the response of the individual patient;the particular compound administered; the mode of administration; thebioavailability characteristics of the preparation administered; thedose regimen selected; the use of concomitant medication; and otherrelevant circumstances.

The term “disease treatable by administration of a 5-HT3 receptorantagonist” includes emesis, migraine, substance abuse and addiction,neurodegenerative and psychiatric disorders such as anxiety anddepression, eating disorders, schizophrenia, cognitive dysfunctionassociated with schizophrenia, Parkinson's disease, Huntington's Chorea,presenile dementias and Alzheimer's disease, and pain; GI disorders suchas dyspepsia, gastroesophagal reflux disease, and irritable bowelsyndrome; and immunological disorders and inflammation such asatherosclerosis, tendomyopathies and fibromyalgia. In a particularembodiment the disease is cognitive dysfunction associated withschizophrenia also known as cognitive impairment associated withschizophrenia.

Representative compounds of the Invention are shown in Table I below:

                  Cpd. No.

                    —Z—R¹                     Salt                    Name                   MW Calcd.                   MS Obs. (M + 1)⁺  1

TFA (1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1]nonan- 7-yl 1-(pyridin-4-yl)-1H-indole-3- carboxylate, 2,2,2-trifluoroacetate 363.4097 364.3  2

TFA N-((1R,5S,7S)-9- methyl-3-oxa-9- azabicyclo [3.3.1]nonan-7-yl)-1-(pyridin-3-yl)- 1H-indole-3- carboxamide, 2,2,2-trifluoroacetate376.4516 377.2  3

TFA N-((1R,5S,7S)- 9-methyl-3-oxa- 9-azabicyclo [3.3.1]nonan-7-yl)-1-(pyridin-2-yl)- 1H-indole-3- carboxamide, 2,2,2-trifluoroacetate376.4516 377.3  4

TFA N-((1R,5S,7S)-9- methyl-3-oxa-9- azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-4-yl)-1H- indole-3-carboxamide, 2,2,2-trifluoroacetate376.4516 377.2  5

TFA (1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl 1-(pyridin-3-yl)-1H-indole- 3-carboxylate, 2,2,2-trifluoroacetate 363.4097 364.2  6

TFA N-((1R,5S,7S)-9- methyl-d₃-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-3-yl)- 1H-indole-3- carboxamide, 2,2,2- trifluoroacetate379.47 380.3  7

TFA (1R,5S,7S)-9-methyl- d₃-3-oxa-9- azabicyclo[3.3.1] nonan-7-yl 1-(pyridin-2-yl)-1H- indole-3-carboxylate, 2,2,2-trifluoroacetate 380.45381.2  8

TFA N-((1R,5S,7S)-9- methyl-d₃-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-2-yl)- 1H-indole-3- carboxamide, 2,2,2- trifluoroacetate379.47 380.3  9

TFA (1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl 1-(1-methyl-1H-pyrazol-4-yl)- 1H-indole-3- carboxylate, 2,2,2-trifluoroacetic acidsalt 366.414 367.15 10

TFA N-((1R,5S,7S)-9- methyl-3-oxa-9- azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-2-yl)- 1H-pyrrolo[2,3-b] pyridine-3-carboxamide, 2,2,2-trifluoroacetic acid salt 377.44 378.25 11

TFA N-((1R,5S,7S)- 9-methyl-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-3-yl)- 1H-pyrrolo[2,3-b] pyridine-3-carboxamide, 2,2,2-trifluoroacetic acid salt 377.44 378.25 12

TFA 5-fluoro-N- ((1R,5S,7S)-9- methyl-3-oxa-9- azabicyclo[3.3.1]nonan-7-yl)-1- (pyridin-2-yl)- 1H-pyrrolo[2,3- b]pyridine-3-carboxamide, 2,2,2- trifluoroaectic acid salt 395.43 396.30 13

TFA 5-fluoro-N- ((1R,5S,7S)-9- methyl-3-oxa-9- azabicyclo[3.3.1]nonan-7-yl)-1- (pyridin-3-yl)- 1H-pyrrolo[2,3- b]pyridine-3-carboxamide, 2,2,2- trifluoroacetic acid salt 395.43 396.25 14

TFA N-((1R,5S,7S)-9- methyl-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(pyridin-2-yl)- 1H-indazole-3- carboxamide, 2,2,2- trifluoroaceticacid salt 377.44 378.30 15

TFA 1-(1-methyl-1H- pyrazol-4-yl)-N- ((1R,5S,7S)- 9-methyl-3-oxa-9-azabicyclo [3.3.1]nonan-7- yl)-1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 379.456 380.30 16

TFA (1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl 1-(1-methyl-1H-pyrazol-3-yl)- 1H-indole-3- carboxylate, 2,2,2-trifluoroacetic acidsalt 366.414 367.20 17

TFA 1-(1-methyl-1H- pyrazol-3-yl)-N- ((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo [3.3.1]nonan-7-yl)- 1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 379.456 380.25 18

TFA (1R,5S,7S)-9-methyl- 3-oxa-9-azabicyclo [3.3.1]nonan-7-yl 1-(1-(2-fluoroethyl)-1H- pyrazol-4-yl)-1H- indole-3-carboxylate, 2,2,2-trifluoroacetic acid salt 412.457 413.30 19

TFA (1R,5S,7S)-3- oxa-9-azabicyclo [3.3.1]nonan-7-yl 1-(2-cyanopyridin-4-yl)- 1H-indole-3- carboxylate, 2,2,2- trifluoroaecticacid salt 388.419 389.20 20

TFA N-((1R,5S,7S)-9- methyl-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(2-methylpyridin- 3-yl)-1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 390.478 391.30 21

TFA N-((1R,5S,7S)-9- methyl-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(4-methylpyridin- 3-yl)-1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 390.478 391.25 22

TFA (1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl 1-(1-methyl-1H-pyrazol-5-yl)- 1H-indole-3- carboxylate, 2,2,2-trifluoroacetic acidsalt 366.414 367.25 23

TFA 1-(1-methyl-1H-pyrazol- 5-yl)-N-((1R,5S,7S)- 9-methyl-3-oxa-9-azabicyclo [3.3.1]nonan-7- yl)-1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 379.456 380.30 24

TFA N-((1R,5S,7S)-9- methyl-3-oxa- 9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol- 4-yl)-1H-indole-3- carboxamide, 2,2,2-trifluoroacetic acid salt 365.429 366.20 25

TFA 1-(1-(difluoromethyl)- 1H-pyrazol-4-yl)- N-((1R,5S,7S)-9-methyl-3-oxa-9- azabicyclo[3.3.1]nonan- 7-yl)-1H-indole-3- carboxamide415.436 416.30 26

TFA (1R,5S,7S)-9-methyl- 3-oxa-9-azabicyclo [3.3.1]nonan-7-yl1-(1-methyl-1H- pyrazol-4-yl)-1H- indole-3-carboxylate 380.440 381.25 27

TFA N-((1R,5S,7S)-3- oxa-9-azabicyclo [3.3.1]nonan-7-yl)-1-(pyridin-3-yl)- 1H-indole-3- carboxamide 362.425 363.25 28

TFA N-((1R,5S,7S)-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl)-1-(1-methyl-1H-pyrazol- 4-yl)-1H-indole- 3-carboxamide 365.429 366.25 29

TFA (1R,5S,7S)-9- methyl-3-oxa- 9-azabicyclo[3.3.1] nonan-7-yl1-(1H-pyrazol- 4-yl)-1H-indole- 3-carboxylate 366.414 367.25 30

TFA N-((1R,5S,7S)-3- oxa-9-azabicyclo [3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)- 1H-indole-3- carboxamide 351.402 352.20 31

TFA N-((1R,5S,7S)-9-ethyl- 3-oxa-9-azabicyclo [3.3.1]nonan-7-yl)-1-(1-methyl- 1H-pyrazol-4-yl)- 1H-indole-3- carboxamide 393.482394.35 32

TFA 3-(3-(((1R,5S,7S)- 9-methyl-3-oxa-9- azabicyclo[3.3.1]nonan-7-yl)carbamoyl)- 1H-indol-1- yl)pyridine 1-oxide 392.451 393.30

EMBODIMENTS Embodiment (A)

In one embodiment, the compound of Formula (I) or pharmaceutical saltthereof as defined in the Summary is where Z is O.

Embodiment (B)

In one embodiment, the compound of Formula (I) or pharmaceutical saltthereof as defined in the Summary is where Z is NR_(a). Within thisembodiment, in another group of compounds R_(a) is hydrogen. Within thisembodiment, in another group of compounds R_(a) is methyl.

Embodiment (C)

In another embodiment, the compound of Formula (I) or pharmaceuticalsalt thereof as defined in the Summary and embodiments (A) and (B) aboveand groups contained therein, in one group of compounds R₁ is a ring offormula

(a) Within groups in embodiments (C), in one group of compounds R₁ is aring of formula (a) or (d). Within (a), in one embodiment, R₁ is a ringof formula

(b) Within groups in embodiments (C), in another group of compounds R₁is a ring of formula (e), (f) or (g). Within (b), in one group ofcompounds R₁ is a ring of formula (e). Within (b), in one group ofcompounds R₁ is a ring of formula (f) or (g). Within (b), in one groupof compounds R₁ is a ring of formula

(i) Within groups in embodiments (C) and embodiments contained thereini.e., (a) and (b) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl. Within thesegroups of compounds in one group of compounds each R₃ is hydrogen.

(ii) Within groups in embodiments (C) and embodiments contained thereini.e., (a) and (b) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl and R₂ ishydrogen. Within these groups of compounds in one group of compounds R₂is hydrogen and each R₃ is hydrogen.

(iii) Within groups in embodiments (C) and embodiments contained thereini.e., (a) and (b) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl and R₂ is C₁₋₆alkyl. Within these groups of compounds in one group of compounds R₂ ismethyl, ethyl, or propyl and each R₃ is hydrogen. Within these groups ofcompounds in one group of compounds R₂ is methyl and each R₃ ishydrogen.

(iv) Within groups in embodiments (C) and embodiments contained thereini.e., (a) and (b) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl and R₂ is C₁₋₆haloalkyl. Within these groups of compounds in one group of compoundseach R₂ is trifluoromethyl, 2-fluoroethyl, or 2,2,2-trifluoroethyl andeach R₃ is hydrogen. Within these groups of compounds in one group ofcompounds R₂ is trifluoromethyl and each R₃ is hydrogen.

(v) Within groups in embodiments (C) and embodiments contained thereini.e., (a) and (b) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl.

Embodiment (D)

In another embodiment, the compound of Formula (I) or pharmaceuticalsalt thereof as defined in the Summary and embodiments (A), and (B)above and groups contained therein, in one group of compounds, is whereR₁ is a ring of formula

(a1) Within groups in embodiments (D), in one group of compounds R₁ is aring of formula (c) or (h). Within this embodiment, in one group ofcompounds the stereochemistry at the chiral carbon is (R) or (S).

(b1) Within groups in embodiments (D), in one group of compounds R¹ is aring of formula (b).

(vi) Within groups in embodiments (D) and embodiments contained thereini.e., (a1) and (b1) and groups contained therein, in one group ofcompounds each R₃ is independently hydrogen or methyl. Within thesegroups of compounds in one group of compounds each R₃ is hydrogen.

Embodiment (E)

In one embodiment, the compound of Formula (I) or pharmaceutical saltthereof as defined in the Summary and embodiments (A), (B), (C), and (D)above and embodiments contained therein, is where R₄ is pyridinyloptionally substituted with one or two substituents independentlyselected from C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ haloalkoxy, C₁₋₆ alkoxy,cyano, or halo.

Within the groups in embodiment (E), it is understood that the pyridinylis represented by the formula below:

Where one of X₆-X₈ is N and the one or two optional substituents, R₇,are independently selected from C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆haloalkoxy, C₁₋₆ alkoxy, cyano, or halo and can be on any carbon atom.

Within the groups in embodiment (E), in another group of compounds X₆ isN. Within the groups in embodiment (E), in another group of compounds X₇is N. Within the groups in embodiment (E), in another group of compoundsX₈ is N.

Embodiment (F)

In one embodiment, the compound of Formula (I) or pharmaceutical saltthereof as defined in the Summary and embodiments (A), (B), (C), and (D)above and embodiments contained therein, is where R₄ is pyrazolyloptionally substituted with one or two substituents independentlyselected from C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ haloalkoxy, C₁₋₆ alkoxy,cyano, or halo.

Within the groups in embodiment (F), it is understood that the pyrazolylis represented by the formula below:

where the R₄ pyrazolyl can be attached by any ring carbon and the one ortwo optional substituents are R₇ and R₈ where R₇, is independentlyselected from C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ haloalkoxy, C₁₋₆ alkoxy,cyano, or halo and can be on any carbon atom and R₈ is hydrogen or C₁₋₆alkyl.

Embodiment (G)

In another embodiment, the compound of Formula (I) or pharmaceuticalsalt thereof as defined in the Summary and embodiments (A), (B), (C),(D), (E), and (F), above and groups contained therein, in one group ofcompounds, each of X₁, X₂, X₃, and X₄ is CR₅. Within this embodiment(G), in another group of compounds each R₅ is hydrogen.

(c1) Within the groups in embodiment (G), in one group of compounds, X₅is N.

(d1) Within the groups in embodiment (G), in another group of compoundsX₅ is CR₆. Within this group of compounds, in one group R₆ is hydrogen

Within this embodiment (G), in another group of compounds each R₅ ishydrogen. Within the groups in embodiment (G), in another group ofcompounds one of R₅ is fluoro or cyano. Within this group of compounds,in another group the R₅ cyano is located at C-5 position, the nitrogenatom substituted with R₄ being position 1. Within this group ofcompounds, in another group of compounds in another group the R₅ fluorois located at C-5 position, the nitrogen atom substituted with R⁴ beingposition 1.

Embodiment (H)

In another embodiment, the compound of Formula (I) or pharmaceuticalsalt thereof as defined in the Summary and embodiments (A), (B), (C),(D), (E), and (F) above and groups is where one of X₁, X₂, X₃, and X₄ isN. Within these groups of compounds in one group of compounds X₁ is N.

(e1) Within the groups in embodiment (H), in one group of compounds X₅is N.

(f1) Within the groups in embodiment (H), in another group of compoundsX₅ is CR₆ and R₆ is hydrogen.

Within the groups in embodiment (H), in one group of compounds each R₅is hydrogen.

Within the groups in embodiment (H), (e1) and (f1), in another group ofcompounds one of R₅ is fluoro, or cyano. Within this group of compounds,in another group the R₅ cyano is located at C-5 position, the nitrogenatom substituted with R₄ being position 1. Within this group ofcompounds, in another group of compounds in another group the R₅ fluorois located at C-5 position, the nitrogen atom substituted with R₄ beingposition 1.

General Synthetic Scheme

Compounds of this invention can be made by the methods depicted in thereaction schemes shown below and other methods known in the art.

The starting materials and reagents used in preparing these compoundsare either available from commercial suppliers such as Aldrich ChemicalCo., (Milwaukee, Wis.), Bachem (Torrance, Calif.), or Sigma (St. Louis,Mo.) or are prepared by methods known to those skilled in the artfollowing procedures set forth in references such as Fieser and Fieser'sReagents for Organic Synthesis, Volumes 1-17 (John Wiley and Sons,1991); Rodd's Chemistry of Carbon Compounds, Volumes 1-5 andSupplementals (Elsevier Science Publishers, 1989); Organic Reactions,Volumes 1-40 (John Wiley and Sons, 1991), March's Advanced OrganicChemistry, (John Wiley and Sons, 4th Edition) and Larock's ComprehensiveOrganic Transformations (VCH Publishers Inc., 1989). These schemes aremerely illustrative of some methods by which the compounds of thisinvention can be synthesized, and various modifications to these schemescan be made and will be suggested to one skilled in the art havingreferred to this disclosure. The starting materials and theintermediates, and the final products of the reaction may be isolatedand purified if desired using conventional techniques, including but notlimited to filtration, distillation, crystallization, chromatography andthe like. Such materials may be characterized using conventional means,including physical constants and spectral data.

Unless specified to the contrary, the reactions described herein takeplace at atmospheric pressure over a temperature range from about −78°C. to about 150° C., more preferably from about 0° C. to about 12° C.and most preferably at about room (or ambient) temperature, e.g., about20° C.

Compounds of Formula (I) can be prepared as illustrated and described inScheme A below.

Step 1 involves formation of the C—N bond between R₄ and N-1 nitrogen ofthe compound of formula 1 where R is an acid protecting group such asC₁₋₆ alkyl. Compounds of formula 1, R₄LG, wherein LG is a leaving groupsuch as sulfonate or halo, and R₄B(OH)₂, or ester thereof, are eithercommercially available or they can be prepared by methods well known inthe art. For example 5-fluoro-2-methylindole-3-carboxylic acid ethylester, 4,5-difluoro-2-methylindole-3-carboxylic acid ethyl ester,1H-indole-3-carboxylic acid, 5-methoxy-, methyl ester,5-fluoro-1H-indole-3-carboxylic acid methyl ester, ethyl5-methyl-1H-indole-3-carboxylate,4,5-difluoro-2-methylindole-3-carboxylic acid ethyl ester,5-cyano-2-methyl-1H-indole-3-carboxylic acid methyl ester,1H-pyrazolo[3,4-b]pyridine-3-carboxylic acid, 5-fluoro-, methyl ester,1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid, 5-methyl-, methyl ester,1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid, 5-fluoro-, methyl ester arecommerically available.

Hydrolysis of the ester group under basic aqueous conditions providesthe corresponding compound of formula 2. Compound 2 is then converted toa compound of Formula (I) where Z is NR_(a) or O or nitrogen protectedderivative thereof, by forming an activated acid derivative of compound2, followed by reaction with R₁R_(a)NH or R₁OH where R₁ is as defined inthe Summary or nitrogen protected derivative thereof. For example, theactivated acid derivative can be mixed anhydride such as with a mixtureof TFAA and TFA in toluene or CDI or Boc₂O; or acid halide such as withoxalyl chloride, thionyl chloride; or under standard using standardpeptide coupling reagents such as HATU in the presence of a base such asN,N-diisopropylethylamine, and a solvent, such as DMF and the like. Whennitrogen protected derivative of R₁R_(a)NH or R₁OH are used, removal ofthe protecting group provides the compound of Formula (I). Amines andalcohols of formula R₁R_(a)NH or R₁OH or nitrogen protected derivativethereof are either commercially available or they can be prepared bymethods known in the art e.g(1S,5R,6S)-4-oxa-1-azabicyclo[3.3.1]nonan-6-ol can be prepared asdescribed in Journal of Medicinal Chemistry, 1993, 36, 683-689.

Alternatively, compound of Formula I can be synthesized by firstcoupling the acid derivative of compound 1 (R is H) with R₁R_(a)NH orR₁OH as described above, followed by formation of N—C bond as describedin Step 1 of Scheme A above.

Detailed descriptions of synthesis of compounds of Formula (I) via aboveprocedures are provided in Working Examples below.

Utility

5-HT3 receptors are known to be expressed in the central nervous systemin regions involving vomiting reflex, processing of pain, cognition andanxiety control and play a role in the pathogenesis of diseases such asemesis, migraine, drug addiction, and neurodegenerative and psychiatricdisorders such as anxiety and depression (see Hewlett et al., 2003 J.Clin. Psychiatry 64, 1025-1030; Kelley et al., 2003a, Eur J. Pharmacol.,461, 19-25; Haus et al., 2000 Scand J Rheumatol Suppl 113, 55-58; andFaris et al., 2006 J affect Disorder 92, 79-90), eating disorders(Hammer et al., 1990 Am J Physiol 259, R627-R636, and Jiang & Gietzen1994 Pharmacol Biochem Behav 47, 59-63), schizophrenia (see Hermann etal. 1996 Biochem Biophys Res Commun 225, 957-960; Sirota et al., 2000 AmJ Psychiatry 157, 287-289; Adler et al., 2005 Am J Psychiatry 162,386-388; Koike et al., Levkovitz et al, 2005 Schizophr Res 76, 67-72),cognitive dysfunction associated with schizophrenia (see Zhang et al.,2006 Schizophr Res 88, 102-110; Akhondzadeh et al., 2009 Schizophr Res107, 206-212), congnitive dysfuntion associated with Parkinson'sdisease, Huntington's Chorea, presenile dementias and Alzheimer'sdisease (see Costall and Naylor 2004 CNS Neurol Disord 3, 27-37)substance abuse and addiction (see Johnson et al., 2002 Psychopharmacology (Berl) 160, 408-413; Johnson, 2004 CNS Drugs 18, 1105-1118;Dawes et al., 2005 Addict Behav 30, 1630-1637, Johnson 2006 Drug AlcoholDepend 84, 256-263), and pain (see Kayser et al, 2007 Pain 130, 235;Glaum et al., 1998 Neurosci Lett 95, 313-317; Schworer & Ramadori 1993Clin Investig 71, 659; Thompson and Lummis 2007 Exp Opin Ther Targets,11, 527-540). In addition, 5-HT3 receptors are expressed in the GI tractand hence may play a role in GI disorders such as dyspepsia,gastroesophagal reflux disease and irritable bowel syndrome (see Graeff1997 Psychiatr Clin North Am 20, 723; Thompson and Lummis 2007 Exp OpinTher Targets, 11, 527-540; Barnes et al. 2009 Neuropharmacology 56,273). Expression of the 5-HT3A subsunit has also been discoveredextraneuronally in immune cells such as monocyes, chondrocytes, T-cells,synovial tissue and platelets (Fiebich et al., 2004 Scan J RheumatolSuppl, 9-11, Stratz et al., 2008 Thromb Haemost 99, 784) and of 5-HT3A,C-E within the lamina propia in the epithelium of the gut mucose(Kapeller et al., J Comp Neuro., 2008; 509: 356-371) thus suggestingthey may be involved in immunological and inflammatory diseases likeatherosclerosis, tendomyopathies and fibromyalgia.

Testing

The 5-HT3 inhibitory activity of the compounds of the present inventioncan be tested using the in vitro assay and in vivo assay described inBiological Example 1, 2, and 3 below.

Administration and Pharmaceutical Composition

In general, the compounds of this invention will be administered in atherapeutically effective amount by any of the accepted modes ofadministration for agents that serve similar utilities. Therapeuticallyeffective amounts of compounds of Formula (I) may range from about 0.01to about 75 mg per kg patient body weight per day, which can beadministered in single or multiple doses. Preferably, the dosage levelwill be about 0.01 to about 10 mg/kg per day; more preferably about 0.5to about 5 mg/kg per day or 0.1-2 mg/kg/day. For oral administration,the compositions are preferably provided in the form of tabletscontaining about 0.5 to about 200 milligrams of the active ingredient,from about 0.5, 1.0, 5.0, 10, 15, 20, 25, 50, 75, 100, 150, or 200milligrams of the active ingredient. The actual amount of the compoundof this invention, i.e., the active ingredient, will depend uponnumerous factors such as the severity of the disease to be treated, theage and relative health of the subject, the potency of the compoundutilized, the route and form of administration, and other factors.Although these dosages are based on an average human subject having amass of about 60 kg to about 70 kg, the physician will be able todetermine the appropriate dose for a patient (e.g., an infant) whosemass falls outside of this weight range.

In general, compounds of this invention will be administered aspharmaceutical compositions by any one of the following routes: oral,systemic (e.g., transdermal, intranasal or by suppository), orparenteral (e.g., intramuscular, intravenous or subcutaneous)administration. The preferred manner of administration is oral using aconvenient daily dosage regimen, which can be adjusted according to thedegree of affliction. Compositions can take the form of tablets, pills,capsules, semisolids, powders, sustained release formulations,solutions, suspensions, elixirs, aerosols, or any other appropriatecompositions.

The choice of formulation depends on various factors such as the mode ofdrug administration (e.g., for oral administration, formulations in theform of tablets, pills or capsules are preferred) and thebioavailability of the drug substance. Recently, pharmaceuticalformulations have been developed especially for drugs that show poorbioavailability based upon the principle that bioavailability can beincreased by increasing the surface area i.e., decreasing particle size.For example, U.S. Pat. No. 4,107,288 describes a pharmaceuticalformulation having particles in the size range from 10 to 1,000 nm inwhich the active material is supported on a crosslinked matrix ofmacromolecules. U.S. Pat. No. 5,145,684 describes the production of apharmaceutical formulation in which the drug substance is pulverized tonanoparticles (average particle size of 400 nm) in the presence of asurface modifier and then dispersed in a liquid medium to give apharmaceutical formulation that exhibits remarkably highbioavailability.

The compositions are comprised of in general, a compound of formula (I)in combination with at least one pharmaceutically acceptable excipient.Acceptable excipients are non-toxic, aid administration, and do notadversely affect the therapeutic benefit of the compound of formula (I).Such excipient may be any solid, liquid, semi-solid or, in the case ofan aerosol composition, gaseous excipient that is generally available toone of skill in the art.

Solid pharmaceutical excipients include starch, cellulose, talc,glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silicagel, magnesium stearate, sodium stearate, glycerol monostearate, sodiumchloride, dried skim milk and the like. Liquid and semisolid excipientsmay be selected from glycerol, propylene glycol, water, ethanol andvarious oils, including those of petroleum, animal, vegetable orsynthetic origin, e.g., peanut oil, soybean oil, mineral oil, sesameoil, etc. Preferred liquid carriers, particularly for injectablesolutions, include water, saline, aqueous dextrose, and glycols.

Compressed gases may be used to disperse a compound of this invention inaerosol form. Inert gases suitable for this purpose are nitrogen, carbondioxide, etc.

Other suitable pharmaceutical excipients and their formulations aredescribed in Remington's Pharmaceutical Sciences, edited by E. W. Martin(Mack Publishing Company, 18th ed., 1990).

The level of the compound in a formulation can vary within the fullrange employed by those skilled in the art. Typically, the formulationwill contain, on a weight percent (wt %) basis, from about 0.01-99.99 wt% of a compound of formula (I) based on the total formulation, with thebalance being one or more suitable pharmaceutical excipients.Preferably, the compound is present at a level of about 1-80 wt %.

The compounds of the present invention may be used in combination withone or more other drugs in the treatment of diseases or conditions forwhich compounds of the present invention or the other drugs may haveutility, where the combination of the drugs together are safer or moreeffective than either drug alone. Such other drug(s) may beadministered, by a route and in an amount commonly used therefore,contemporaneously or sequentially with a compound of the presentinvention. When a compound of the present invention is usedcontemporaneously with one or more other drugs, a pharmaceuticalcomposition in unit dosage form containing such other drugs and thecompound of the present invention can be used. However, the combinationtherapy may also include therapies in which the compound of the presentinvention and one or more other drugs are administered on differentoverlapping schedules. It is also contemplated that when used incombination with one or more other active ingredients, the compounds ofthe present invention and the other active ingredients may be used inlower doses than when each is used singly.

Accordingly, the pharmaceutical compositions of the present inventionalso include those that contain one or more other active ingredients, inaddition to a compound of the present invention.

The above combinations include combinations of a compound of the presentinvention not only with one other active compound, but also with two ormore other active compounds. Likewise, compounds of the presentinvention may be used in combination with other drugs that are used inthe prevention, treatment, control, amelioration, or reduction of riskof the diseases or conditions for which compounds of the presentinvention are useful. Such other drugs may be administered, by a routeand in an amount commonly used therefore, contemporaneously orsequentially with a compound of the present invention. Accordingly, thepharmaceutical compositions of the present invention also include thosethat also contain one or more other active ingredients, in addition to acompound of the present invention. The weight ratio of the compound ofthe present invention to the second active ingredient may be varied andwill depend upon the effective dose of each ingredient. Generally, aneffective dose of each will be used.

In one embodiment, the compound of the present invention may beadministered in combination with anti-Alzheimer's agents, beta-secretaseinhibitors, gamma-secretase inhibitors, HMG-CoA reductase inhibitors,NSAID's including ibuprofen, vitamin E, and anti-amyloid antibodies. Inanother embodiment, the compound of the present invention may beadministered in combination with sedatives, hypnotics, anxiolytics,antipsychotics, antianxiety agents, cyclopyrrolones, imidazopyridines,pyrazolopyrimidines, minor tranquilizers, melatonin agonists andantagonists, melatonergic agents, benzodiazepines, barbiturates, mGlu2/3agonists, 5HT-2 antagonists, PDE10 antagonists, GlyT1 inhibitors, andthe like, such as: adinazolam, allobarbital, alonimid, alprazolam,amisulpride, amitriptyline, amobarbital, amoxapine, aripiprazole,bentazepam, benzoctamine, brotizolam, bupropion, busprione,butabarbital, butalbital, capuride, carbocloral, chloral betaine,chloral hydrate, clomipramine, clonazepam, cloperidone, clorazepate,chlordiazepoxide, clorethate, chlorpromazine, clozapine, cyprazepam,desipramine, dexclamol, diazepam, dichloralphenazone, divalproex,diphenhydramine, doxepin, estazolam, ethchlorvynol, etomidate, fenobam,flunitrazepam, flupentixol, fluphenazine, flurazepam, fluvoxamine,fluoxetine, fosazepam, glutethimide, halazepam, haloperidol,hydroxyzine, imipramine, lithium, lorazopam, lormetazepam, maprotiline,mecloqualone, melatonin, mephobarbital, meprobamate, methaqualone,midaflur, midazolam, nefazodone, nisobamate, nitrazopam, nortriptyline,olanzapine, oxazepam, paraldehyde, paroxetine, pentobarbital, perlapine,perphenazine, phenelzine, phenobarbital, prazepam, promethazine,propofol, protriptyline, quazepam, quetiapine, reclazepam, risperidone,roletamide, secobarbital, sertraline, suproclone, temazopam,thioridazine, thiothixene, tracazolate, kanylcypromaine, trazodone,triazolam, trepipam, tricetamide, triclofos, trifluoperazine,trimetozine, trimipramine, uldazepam, venlafaxine, zaleplon,ziprasidone, zolazepam, zolpidem,[4-(3-fluoro-5-trifluoromethylpyridin-2-yl)piperazin-1-yl][5-methanesulfonyl-2-((S)-2,2,2-trifluoro-1-methylethoxy)phenyl]methanone(RG1678), glyt1 inhibitors disclosed in U.S. Pat. No. 7,538,114, Table 1in column 14, and salts thereof, and combinations thereof.

In another embodiment, the compound of the present invention may beadministered in combination with levodopa (with or without a selectiveextracerebral decarboxylase inhibitor such as carbidopa or benserazide),anticholinergics such as biperiden (optionally as its hydrochloride orlactate salt) and trihexyphenidyl (benzhexyl)hydrochloride, COMTinhibitors such as entacapone, MOA-B inhibitors, antioxidants, A2aadenosine receptor antagonists, cholinergic agonists, NMDA receptorantagonists, serotonin receptor antagonists and dopamine receptoragonists such as alentemol, bromocriptine, fenoldopam, lisuride,naxagolide, pergolide and prarnipexole. It will be appreciated that thedopamine agonist may be in the form of a pharmaceutically acceptablesalt, for example, alentemol hydrobromide, bromocriptine mesylate,fenoldopam mesylate, naxagolide hydrochloride and pergolide mesylate.Lisuride and pramipexol are commonly used in a non-salt form.

In another embodiment, the compound of the present invention may beadministered in combination with a compound from the phenothiazine,thioxanthene, heterocyclic dibenzazepine, butyrophenone,diphenylbutylpiperidine and indolone classes of neuroleptic agent.Suitable examples of phenothiazines include chlorpromazine,mesoridazine, thioridazine, acetophenazine, fluphenazine, perphenazineand trifluoperazine. Suitable examples of thioxanthenes includechlorprothixene and thiothixene. An example of a dibenzazepine isclozapine. An example of a butyrophenone is haloperidol. An example of adiphenylbutylpiperidine is pimozide. An example of an indolone ismolindolone. Other neuroleptic agents include loxapine, sulpiride andrisperidone. It will be appreciated that the neuroleptic agents whenused in combination with the subject compound may be in the form of apharmaceutically acceptable salt, for example, chlorpromazinehydrochloride, mesoridazine besylate, thioridazine hydrochloride,acetophenazine maleate, fluphenazine hydrochloride, flurphenazineenathate, fluphenazine decanoate, trifluoperazine hydrochloride,thiothixene hydrochloride, haloperidol decanoate, loxapine succinate andmolindone hydrochloride. Perphenazine, chlorprothixene, clozapine,haloperidol, pimozide and risperidone are commonly used in a non-saltform. Thus, the compound of the present invention may be administered incombination with acetophenazine, alentemol, aripiprazole, amisulpride,benzhexyl, bromocriptine, biperiden, chlorpromazine, chlorprothixene,clozapine, diazepam, fenoldopam, fluphenazine, haloperidol, levodopa,levodopa with benserazide, levodopa with carbidopa, lisuride, loxapine,mesoridazine, molindolone, naxagolide, olanzapine, pergolide,perphenazine, pimozide, pramipexole, quetiapine, risperidone, sulpiride,tetrabenazine, trihexyphenidyl, thioridazine, thiothixene,trifluoperazine or ziprasidone.

In another embodiment, the compound of the present invention may beadministered in combination with an anti-depressant or anti-anxietyagent, including norepinephrine reuptake inhibitors (including tertiaryamine tricyclics and secondary amine tricyclics), selective serotoninreuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs),reversible inhibitors of monoamine oxidase (RIMAs), serotonin andnoradrenaline reuptake inhibitors (SNRIs), corticotropin releasingfactor (CRF) antagonists, adrenoreceptor antagonists, neurokinin-1receptor antagonists, atypical anti-depressants, benzodiazopines, 5-HTAagonists or antagonists, especially 5-HTA partial agonists, andcorticotropin releasing factor (CRF) antagonists. Specific agentsinclude: amitriptyline, clomipramine, doxepin, imipramine andtrimipramine; amoxapine, desipramine, maprotiline, nortriptyline andprotriptyline; fluoxetine, fluvoxamine, paroxetine and sertraline;isocarboxazid, phenelzine, tranylcypromine and selegiline; moclobemide,venlafaxine; duloxetine; aprepitant; bupropion, lithium, nefazodone,trazodone and viloxazine; alprazolam, chlordiazepoxide, clonazopam,chlorazepate, diazopam, halazepam, lorazepam, oxazopam and prazepam;buspirone, flesinoxan, gepirone and ipsapirone, and pharmaceuticallyacceptable salts thereof.

EXAMPLES

The following preparations of compounds of Formula (I) are given toenable those skilled in the art to more clearly understand and topractice the present invention. They should not be considered aslimiting the scope of the invention, but merely as being illustrativeand representative thereof.

Synthetic Procedures Reference 1 Synthesis of (1R,5S,7S)-tert-butyl7-hydroxy-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate

Sodium borohydride (259 mg, 6.84 mmol) was added portion-wise to asolution of (1R,5S)-tert-butyl7-oxo-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate (550 mg, 2.279 mmol)in MeOH (4559 μl) at 0° C. After 5 min, the reaction mixture was allowedto warm to RT then stirred for 30 min. The mixture was concentratedunder reduced pressure, dissolved in EtOAc and washed with brine. Thecombined organic layers were dried over anhydrous Na₂SO₄, filtered andconcentrated under reduced pressure to afford the title compound as awhite solid, which was used without further purification.

Reference 2 Synthesis of(1R,5S,7S)-9-methyl-d₃-oxa-9-azabicyclo[3.3.1]nonan-7-amine

Step 1: (1R,5S)-9-Methyl-d₃-oxa-9-azabicyclo[3.3.1]nonan-7-one

To a solution of sodium dihydrogenphosphate hydrate (22.30 g, 162 mmol)and 2-hydroxypropane-1,2,3-tricarboxylic acid (4.90 g, 25.5 mmol) inwater (Volume: 506 ml) was added in turn methyl-d₃-amine hydrogenchloride (5 g, 70.9 mmol) and 3-oxopentanedioic acid (11.91 g, 82 mmol).The pH was adjusted to 4.6 with a 10% aqueous solution of NaOH. Asolution of 2,2′-oxydiacetaldehyde (3.62 g, 35.4 mmol) in 8 mL MeOH wasadded at RT and the resulting mixture was stirred at RT for 3 days. 10%aqueous NaOH was used to basify the reaction solution, and extractedwith DCM (100 mL). Purification with column chromatography (SiO₂;DCM/MeOH) gave the title compound as a white solid.

Step 2: (1R,5S)-9-methyl-d₃-3-oxa-9-azabicyclo[3.3.1]nonan-7-one oxime

A solution of (1R,5S)-9-methyl-d₃-oxa-9-azabicyclo[3.3.1]nonan-7-one(1.65 g, 10.43 mmol), hydroxylamine hydrochloride (0.761 g, 10.95 mmol)and pyridine (0.843 ml, 10.43 mmol) in EtOH (Volume: 52.1 ml) was heatedat 75° C. for 3 h. After 0.2 mL of triethylamine was added to thereaction solution, the solvent was removed. Purification by columnchromatography (SiO₂; DCM/MeOH) gave the title compound as a whitesolid.

Step 3: (1R,5S,7S)-9-Methyl-d₃-oxa-9-azabicyclo[3.3.1]nonan-7-amine

Sulfuric acid (1.108 ml, 20.78 mmol) was added dropwise over 15 min to awell-stirred solution of aluminum(III) lithium hydride (1.0 M in THF,41.6 ml, 41.6 mmol) in THF (Volume: 41.6 ml) at 0° C. The mixture wasstirred for another hour at 0° C. and then(1R,5S)-9-methyl-d₃-3-oxa-9-azabicyclo[3.3.1]nonan-7-one oxime (1.8 g,10.39 mmol) was added portionwise at 0° C. The reaction mixture washeated under reflux (80° C.) for 1.5 h. To the well-stirred reactionmixture, 1.58 mL of water, 2.37 mL of 10 M NaOH and 3.95 mL of waterwere subsequently added at 0° C. The resultant suspension was filteredthrough a pad of Celite and washed with THF. The combined organic phasewas concentrated under reduced pressure to afford the title compound asa pale-yellow oil, which was used without further purification.

Reference 3 Synthesis of(1R,5S,7S)-9-(trifluoromethyl)-3-oxa-9-azabicyclo[3.3.1]nonan-7-amine2,2,2-trifluoroacetate

Step 1: Benzyl (1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-ylcarbamate

Benzyl chloroformate (330 μl, 2.319 mmol) was added to a solution of(1R,5S,7S)-tert-butyl7-amino-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate2,2,2-trifluoroacetate (751.3 mg, 2.108 mmol) and triethylamine (619 μl,4.43 mmol) in DCM (10 ml) at RT. After 14 h, trifluoroacetic acid (2.4mL, 31.6 mmol) was added to the reaction mixture. After 15 min, themixture was concentrated, dissolved with DMF, filtered, and purified byHPLC followed by neutralization (K₂CO₃) to afford the title compound asa colorless oil.

Step 2: Benzyl((1R,5S,7S)-9-(trifluoromethyl)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)carbamate

A solution of benzyl(1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-ylcarbamate (27 mg, 0.098mmol) and dibromodifluoromethane (18.06 μl, 0.195 mmol) in DMSO (489 μl)was treated with tetrakis(dimethylamino)ethylene (50.1 μl, 0.215 mmol),dropwise at 0° C. The mixture slowly warmed to RT overnight then waspoured into a 1:1 mixture of NaHCO₃/Na₂S₂O₃ and extracted twice withEt₂O. The combined extracts were concentrated and purified by prep-TLCto give the title compound as a yellow oil.

Step 3:(1R,5S,7S)-9-(Trifluoromethyl)-3-oxa-9-azabicyclo[3.3.1]nonan-7-amine2,2,2-trifluoroacetate

In a vial containing benzyl((1R,5S,7S)-9-(trifluoromethyl)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)carbamate(10 mg, 0.029 mmol), palladium on carbon (10 wt %, 1.020 mg, 9.58 μmol),and TFA (4.47 μl, 0.058 mmol) in MeOH (Volume: 145 μl) was purged withhydrogen gas and left under 1 atm H₂ atmosphere for 2 h. Filtrationthrough a pad of Celite/MgSO₄ (1:1) followed by concentration gave thetitle compound as a colorless film, which was used without furtherpurification.

Reference 4 Synthesis of (1S,5R,6S)-4-oxa-1-azabicyclo[3.3.1]nonan-6-ol;(1R,5S,6R)-4-oxa-1-azabicyclo[3.3.1]nonan-6-ol

Step 1: Ethyl 4-(3-ethoxy-3-oxopropyl)morpholine-2-carboxylate

A mixture of ethyl morpholine-2-carboxylate (3 g, 18.85 mmol) and ethylacrylate (5 ml, 18.85 mmol) was heated at 100° C. for 14 h. The reactionwas cooled to RT then diluted with Et₂O and extracted with aqueous 3MHCl. The combined aqueous layers were basified by solid K₂CO₃ andextracted with DCM. The combined organic layers were dried overanhydrous Na₂SO₄, filtered and concentrated under reduced pressure toafford the title compound as a pale-yellow oil, which was used withoutfurther purification.

Step 2: (1S,5R)-4-Oxa-1-azabicyclo[3.3.1]nonan-6-one(1R,5S)-4-Oxa-1-azabicyclo[3.3.1]nonan-6-one

A solution of ethyl 4-(3-ethoxy-3-oxopropyl)morpholine-2-carboxylate(3.07 g, 11.84 mmol) in toluene (8 ml) was added to a suspension ofpotassium 2-methylpropan-2-olate (3.65 g, 32.6 mmol) in toluene (39.5ml) at 120° C. After being stirred at 120° C. for 3 h, the reactionmixture was cooled to RT and extracted with water (20 mL). The aqueouslayer was treated with conc. HCl (20 ml, 240 mmol) then heated at 110°C. for 14 h. The reaction mixture was cooled to RT then concentratedunder reduced pressure. The resulting solid was taken up in saturatedaq. K₂CO₃ and extracted with DCM. The combined organic layers were driedover anhydrous Na₂SO₄, filtered and concentrated under reduced pressureto afford the title compounds as a brown oil, which was used withoutfurther purification.

Step 3: (1S,5R,6S)-4-Oxa-1-azabicyclo[3.3.1]nonan-6-ok(1R,5S,6R)-4-Oxa-1-azabicyclo[3.3.1]nonan-6-ol

Sodium borohydride (53.6 mg, 1.417 mmol) was added to a solution of(1S,5R)-4-oxa-1-azabicyclo[3.3.1]nonan-6-one and(1R,5S)-4-oxa-1-azabicyclo[3.3.1]nonan-6-one (100 mg, 0.708 mmol) inMeOH (3542 μl) at 0° C. The reaction mixture was stirred at RT for 30min, then concentrated under reduced pressure. The residue was taken upin EtOAc and washed with brine. The organic layer was dried overanhydrous Na₂SO₄, filtered and concentrated under reduced pressure toafford the title compounds as a yellow oil, which was used withoutfurther purification

Reference 5 Synthesis of 1-(pyridin-4-yl)-1H-indole-3-carboxylic acid

Step 1: Methyl 1-(pyridin-4-yl)-1H-indole-3-carboxylate

To a vial containing methyl 1H-indole-3-carboxylate (402 mg, 2.297mmol), pyridin-4-ylboronic acid (847 mg, 6.89 mmol), copper (II) acetate(542 mg, 2.99 mmol), 4 {acute over (Å)} molecular sieves (4 g) and1,10-phenanthroline (828 mg, 4.59 mmol) were added DCM (9 ml) andtriethylamine (0.320 ml, 2.297 mmol). The mixture was stirred at RT for4 days then filtered through a pad of Celite (washed with MeOH).Evaporation and purification by HPLC (after dilution with DMF andfiltration) afforded the title compound as a yellow solid.

Step 2: 1-(Pyridin-4-yl)-1H-indole-3-carboxylic acid

To a solution of methyl 1-(pyridin-4-yl)-1H-indole-3-carboxylate (92 mg,0.365 mmol) in water (365 μl) and MeOH (365 μl) was added KOH (102 mg,1.823 mmol). The mixture was heated at 90° C. for 1 h then the MeOH wasremoved under reduced pressure. The residual aqueous layer wasneutralized with 1M HCl (pH=6-7) then extracted with EtOAc. The combinedorganic layers were dried over anhydrous MgSO₄, filtered, concentratedto afford the title compound as a yellow solid, which was used withoutfurther purification.

Proceeding as described above, 1-(pyridin-3-yl)-1H-indole-3-carboxylicacid was prepared.

Reference 6 Synthesis of 1-(pyridin-2-yl)-1H-indole-3-carboxylic acid

Step 1: Methyl 1-(pyridin-2-yl)-1H-indole-3-carboxylate

Sodium hydride (45.7 mg, 1.142 mmol, 60% dispersion in mineral oil) wasadded to a solution of methyl 1H-indole-3-carboxylate (200 mg, 1.142mmol) in DMF (2283 μl) at RT. After 30 min, 2-fluoropyridine (99 μl,1.142 mmol) was added to the mixture and the resulting suspension washeated at 120° C. for 14 h. The reaction mixture was diluted with DMF,filtered, and purified by HPLC to afford the title compound as a whitesolid.

Step 2: 1-(Pyridin-2-yl)-1H-indole-3-carboxylic acid

The title compound was synthesized by utilizing similar conditions asdescribed in Reference 5, Step 2.

Reference 7 Synthesis of(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1H-indole-3-carboxylate

To a solution of 1H-indole-3-carboxylic acid (250 mg, 1.551 mmol) inPhMe (5171 μl) was added TFAA (219 μl, 1.551 mmol) then TFA (1293 μl).The mixture was stirred for 30 min then commercially available(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-ol (203 mg, 1.293mmol) was added. The reaction mixture stirred at RT for 1 h then waspoured into aq NaHCO₃ and stirred until pH=7 and bubbling stopped. Thereaction mixture was extracted with EtOAc and dried over MgSO₄.Purification by ISCO (0-20% MeOH/DCM) yielded the title compound as apink solid.

Reference 8 Synthesis of (1R,5S,7S)-tert-butyl7-((1H-indole-3-carbonyl)oxy)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate

Step 1: (1R,5S,7S)-9-benzyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-ol

Sodium borohydride (24.54 g, 649 mmol) was added portionwise over 30 minto a suspension of (1R,5S)-9-benzyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-one(50 g, 216 mmol) in MeOH (540 ml) and THF (540 ml) at 0° C. The mixturewas allowed to gradually warm to RT over 1 h. After an additional hourat RT, the mixture was concentrated and the white residue waspartitioned between ethyl acetate and brine. The combined organic layerswere dried over Na₂SO₄, filtered and concentrated under reduced pressureto afford the title compound as a white solid, which was used withoutfurther purification.

Step 2: (1R,5S,7S)-9-benzyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-ol

2,2,2-Trifluoroacetic anhydride (34.5 ml, 244 mmol) and TFA (123 ml)were subsequently added to a solution of 1H-indole-3-carboxylic acid(39.4 g, 244 mmol) in toluene (987 ml) at RT. After 30 min,(1R,5S,7S)-9-benzyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-ol (51.8 g, 222mmol) was added to the mixture in one portion at RT. After 2 h, themixture was concentrated under reduced pressure to the half of theoriginal volume. Then, 800 mL of 10% Na₂CO₃ (aq) was added. The mixturewas concentrated under reduced pressure until most of the organicsolvent was removed. The product was extracted with ethyl acetate andthe combined organic layers were washed with brine, dried over Na₂SO₄,filtered and concentrated under reduced pressure. The residual darkpurple solid was triturated with Et₂O/EtOAc (4:1) to yield the titlecompound as a white-pink solid.

Step 3: (1R,5S,7 S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1H-indole-3-carboxylate, hydrogen chloride salt

A suspension of (1R,5S,7S)-9-benzyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1H-indole-3-carboxylate (2 g, 5.31 mmol) and palladium on carbon (200mg, 1.879 mmol, 10 wt %) in EtOH (4.43 ml), THF (4.43 ml) and 3N HCl(4.43 ml) was stirred at RT under a hydrogen atmosphere (balloon) for 14h. Then, the mixture was filtered through a pad of Celite and thefiltrate was concentrated under reduced pressure to afford the titlecompound as a pink solid, which was used without further purification.

Step 4: (1R,5S,75)-tert-butyl7-((1H-indole-3-carbonyl)oxy)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate

Di-tert-butyl dicarbonate (1.275 g, 5.84 mmol) was added in one portionto a suspension of (1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1H-indole-3-carboxylate hydrochloride (1.714 g, 5.31 mmol) andtriethylamine (1.628 ml, 11.68 mmol) in THF (26.6 ml) at RT. After 1 h,the mixture was partitioned between sat. NH₄Cl (aq) and ethyl acetate.The aqueous layer was extracted with ethyl acetate and combined organiclayers were washed with brine, dried over anhydrous Na₂SO₄, filtered andconcentrated under reduced pressure to afford the title compound as apale-brown oil, which was used without further purification.

Reference 9 Synthesis of1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid

Step 1: methyl 1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate

Sodium hydride (22.70 mg, 0.568 mmol, 60% suspension in mineral oil) wasadded to a solution of methyl 1H-pyrrolo[2,3-b]pyridine-3-carboxylate(100 mg, 0.568 mmol) in DMF (1419 μl) at RT. After 10 min,2-fluoropyridine (48.8 μl, 0.568 mmol) was added to the mixture and themixture was heated at 100° C. for 14 h. After being cooled to RT, thereaction mixture was directly purified by HPLC followed byneutralization (aq. NaHCO₃) to afford the title compound as a colorlessfilm.

Step 2: 1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid

Potassium hydroxide (11.30 mg, 0.201 mmol) was added to a solution ofmethyl 1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylate (10.2mg, 0.040 mmol) in MeOH (67.1 μl) and water (67.1 μl) at RT. The mixturewas heated at 90° C. for 2 h. The organic layer was extracted into ethylacetate after acidifying the mixture with 0.5 N citric acid. Thecombined organic layers were washed with brine, dried over Na₂SO₄,filtered and concentrated under reduced pressure to afford the titlecompound as a white solid, which was used without further purification.

The following carboxylic acids were prepared by a similar procedure:

5-fluoro-1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxylic acidand 1-(pyridin-2-yl)-1H-indazole-3-carboxylic acid.

Example 1 Synthesis of (1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(pyridin-3-yl)-1H-indole-3-carboxylate bis(2,2,2-trifluoroacetate)

Step 1: (1R,5S,7S)-tert-Butyl7-((1-(pyridin-3-yl)-1H-indole-3-carbonyl)oxy)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate

Copper(I) iodide (21.99 mg, 0.115 mmol) was added to a suspension of(1R,5S,7S)-tert-butyl7-((1H-indole-3-carbonyl)oxy)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate(163.6 mg, 0.423 mmol), 3-bromopyridine (37.1 μl, 0.385 mmol),trans-N,N′-dimethylcyclohexane-1,2-diamine (36.9 μl, 0.231 mmol) andpotassium phosphate (172 mg, 0.808 mmol) in toluene (Volume: 770 μl) atRT. The mixture was heated at 110° C. for 14 h. The mixture was thenconcentrated and directly purified by column chromatography (SiO₂:EA/hex) to afford the title compound as a yellow foam.

Step 2 (1R,5S,7S)-3-Oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(pyridin-3-yl)-1H-indole-3-carboxylate bis(2,2,2-trifluoroacetate)

TFA (Volume: 356 μl, Ratio: 1.000) was added to a solution of(1R,5S,7S)-tert-butyl741-(pyridin-3-yl)-1H-indole-3-carbonyl)oxy)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate(164.8 mg, 0.356 mmol) in DCM (Volume: 356 μl, Ratio: 1.000) at rt.After 15 min, the mixture was diluted with DMF, filtered and purified byHPLC to afford the title compound as a pale-yellow oil to afford thetitle compound as a yellow oil. MS (ESI, pos. ion) m/z: 364.2 (M+1).

The following compounds were prepared by a similar procedure, where Bocgroup was removed either with TFA or HCl:(1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylate,2,2,2-trifluoroacetic acid salt;(1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-methyl-1H-pyrazol-3-yl)-1H-indole-3-carboxylate,2,2,2-trifluoroacetic acid salt; and(1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-methyl-1H-pyrazol-5-yl)-1H-indole-3-carboxylate,2,2,2-trifluoroacetic acid salt.

Example 2 Synthesis of1-(1-methyl-1H-pyrazol-3-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

To a mixture of 1-(1-methyl-1H-pyrazol-3-yl)-1H-indole-3-carboxylic acidhydrochloride (25 mg, 0.090 mmol) in DMF (Volume: 900 μl) was added HATU(37.7 mg, 0.099 mmol) and N-ethyl-N-isopropylpropan-2-amine (79 μl,0.450 mmol). After the reaction mixture was stirred at rt for 15 min,(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-amine2,2,2-trifluoroacetate (29.2 mg, 0.108 mmol) was added and stirring wascontinued for 2 h. HPLC purification gave the title compound as a whitesolid. MS (ESI, pos. ion) m/z: 380.25 (M+1)

The following compounds were prepared by a similar procedure, eitherwith commercially available carboxylic acids or those synthesizedaccording to reference compound procedures:

1-(1-methyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,1-(1-methyl-1H-pyrazol-5-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt; and1-(1-benzyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide2,2,2-trifluoroacetate.

Example 3 Synthesis of(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-(2-fluoroethyl)-1H-pyrazol-4-yl)-1H-indole-3-carboxylate,2,2,2-trifluoroacetic acid salt

Step 1: 4-bromo-1-(2-fluoroethyl)-1H-pyrazole

Sodium hydride (24.22 mg, 0.606 mmol, 60% suspension in mineral oil) wasadded to a solution of 4-bromo-1H-pyrazole (89 mg, 0.606 mmol) in DMF(3028 μl) at RT. After 15 min, 1-bromo-2-fluoroethane (100 mg, 0.787mmol) was added to the mixture. After 30 min, the mixture was dilutedwith DMF and purified by HPLC, followed by neutralization (K₂CO₃), toafford the title compound as a colorless oil.

Step 2: (1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-(2-fluoroethyl)-1H-pyrazol-4-yl)-1H-indole-3-carboxylate,2,2,2-trifluoroacetic acid salt

A mixture of (1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1H-indole-3-carboxylate (50 mg, 0.166 mmol),4-bromo-1-(2-fluoroethyl)-1H-pyrazole (35.3 mg, 0.183 mmol), copper(I)iodide (9.51 mg, 0.050 mmol), N1,N1-dimethylethane-1,2-diamine (8.80 mg,0.100 mmol) and potassium phosphate (74.2 mg, 0.350 mmol) in toluene(333 μl) was heated at 120° C. for 5 h. HPLC purification gave the titlecompound as a light-brown oil. MS (ESI, pos. ion) m/z: 413.30 (M+1).

Example 4 Synthesis ofN-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

A mixture of1-((1-benzyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide2,2,2-trifluoroacetate (85 mg, 0.149 mmol) and 10% Pd—C (120 mg) in MeOH(1.0 ml) was stirred at RT under H₂ for 2 days. Filtration andconcentration afforded the title compound as a white solid. MS (ESI,pos. ion) m/z: 366.20 (M+1).

Example 5 Synthesis of1-(1-methyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

Step 1: methyl 1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylate, TFA

To a sealed tube was added copper(I) iodide (65.2 mg, 0.342 mmol),methyl 1H-indole-3-carboxylate (200 mg, 1.142 mmol) and potassiumphosphate (509 mg, 2.397 mmol), then the reaction vessel was evacuatedand purged with nitrogen (3×). Next, 4-bromo-1-methyl-1H-pyrazole (184mg, 1.142 mmol) and (1R,2R)—N1,N2-dimethylcyclohexane-1,2-diamine (109μl, 0.685 mmol) were added, followed by toluene (1142 μl). The reactiontube was evacuated and purged with nitrogen, then sealed and heated at110° C. for 24 h. HPLC purification provided the title compound as acolorless oil.

Step 2: 1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylic acidhydrochloride

To a solution of methyl1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylate, TFA (3.5 mg, 9.48μmol) in MeOH (95 μl) was added a solution of aq. KOH (33.2 μl, 0.066mmol, 2 M). The reaction mixture was stirred at RT overnight, thenacidified with 1N HCl. The solvent was evaporated under reduced pressureand the residue was dried under vacuum overnight. The title compound wasused without further purification.

Step 3:1-(1-methyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

To a mixture of 1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylic acidhydrochloride (2.6 mg, 9.36 μmol) in DMF (187 μl) was added HATU (4.27mg, 0.011 mmol) and DIPEA (8.18 μl, 0.047 mmol). After the reactionmixture was stirred at RT for 15 min,(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-amine, TFA (3.04mg, 0.011 mmol) was added and stirring was continued for 2 h. HPLCpurification afforded the title compound as a white solid. MS (ESI, pos.ion) m/z: 380.30 (M+1).

Example 61-(1-(difluoromethyl)-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

Step 1:1-(1-(bromodifluoromethyl)-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

To a solution ofN-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt (30 mg, 0.063 mmol) in DMF (Volume: 626μl) at 0° C. was added sodium hydride (7.51 mg, 0.188 mmol) andtetrabutylammonia bromide (0.202 mg, 0.626 μmol). After the resultingsolution was stirred for 1 h, a solution of dibromodifluoromethane (5.78μl, 0.063 mmol) in 0.1 mL DMF was added. The reaction mixture wasgradually warmed up to RT over 2 h and stirred at RT for 2 h. HPLCpurification afforded the title compound as a white solid.

Step 2:1-(1-(difluoromethyl)-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

A solution of1-(1-(bromodifluoromethyl)-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt (4 mg, 6.58 μmol) and TBAF (3.44 mg,0.013 mmol) in sulfolane (Volume: 32.9 μl) was slowly heated to 170-180°C. HPLC purification afforded the title compound as a white solid film.MS (ESI, pos. ion) m/z: 416.30 (M+1).

Example 7N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

Step 1: ten-Butyl(1R,5S,7S)-7-(1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamido)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate

To a solution of 1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylicacid hydrochloride (25 mg, 0.090 mmol) and HATU (37.7 mg, 0.099 mmol) inDMF (Volume: 450 n1) was added N-ethyl-N-isopropylpropan-2-amine (62.9μl, 0.360 mmol). After the reaction solution was stirred at RT for 15min, (1R,5S,7S)-tert-butyl7-amino-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate (24.00 mg, 0.099mmol) was added. The stirring was continued for 1 h. HPLC purificationfollowed by ISCO (0-20% MeOH in DCM) purification gave the titlecompound as a white solid.

Step 2:N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

A solution of tert-Butyl(1R,5S,7S)-7-(1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamido)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate(18.1 mg, 0.039 mmol) in TFA (Volume: 194 μl, Ratio: 1) and DCM (Volume:194 μl, Ratio: 1) was stirred at RT for 1 h. Removal of the solvent gavethe title compound as a white solid. MS (ESI, pos. ion) m/z: 366.25(M+1).

The following compound was prepared by a similar procedure:

-   N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-indole-3-carboxamide.

Example 8N-((1R,5S,7S)-9-ethyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt

A mixture ofN-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)-1H-indole-3-carboxamide,2,2,2-trifluoroacetic acid salt (12 mg, 0.025 mmol), triethylamine (5.13μl, 0.038 mmol), and acetaldehyde (2.120 μl, 0.038 mmol) in DCE (Volume:250 μl) was stirred for 10 min at RT. Then, sodium triacetoxyhydroborate(10.61 mg, 0.050 mmol) was added at RT. The mixture was stirred for 16 hand quenched with a few drops of water. HPLC purification afforded thetitle compound as a white solid. MS (ESI, pos. ion) m/z: 394.35 (M+1).

Example 93-(3-(((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)carbamoyl)-1H-indol-1-yl)pyridine1-oxide, 2,2,2-trifluoroacetic acid salt

A mixture ofN-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-indole-3-carboxamide(20 mg, 0.053 mmol) and meta-chloroperoxybenzoic acid (10.08 mg, 0.058mmol) in DCM (Volume: 0.8 ml) was stirred at RT for 2 h. HPLCpurification gave the title compound as a white solid. MS (ESI, pos.ion) m/z: 393.30 (M+1).

BIOLOGICAL EXAMPLES Biological Example 1 Inhibition of Ca Flux Activityof 5-HT3 In Vitro Assay

The 5-HT3 antagonist activity of the compounds of the invention wasdetermined by measuring the ability of the compounds to inhibit thecalcium flux activity of 3HT3a receptor expressed in HEK-293T cells.HEK-293T cells were transfected with the 5-HT3a expression constructusing Xtreme Gene 9 (Roche) in 150 mm tissue culture treated plates andincubated for 24 hours at 37° C. Cells were then split and plated at adensity of 60K cells/well in poly-lysine coated, black 96-well plateswith clear bottoms (BD BioSciences) and incubated overnight at 37° C.Growth media was removed and cells loaded with 200 uL calcium indicatordye in HBSS containing 20 mM HEPES (Calcium 5 Assay kit, MolecularDevices) and incubated at 37° C. for 1 hour. While cells wereincubating, the 10× antagonist and agonist/antagonist addition plateswere made. For 10× antagonist plate: half log serial dilutions (finalconcentrations range from 10⁻⁷ through 10⁻¹⁰ with the bottom well anegative, no ligand control) were made from test compounds in DMSO at a1000× concentration and then diluted to 10× in HBSS/20 mM HEPES. Foraddition plate: 5HT was diluted to 100× in HBSS/20 mM HEPES (finalconcentration in the assay-216 nM) and 15 uL was added to each well ofthe addition plate, 15 uL of 10× compound was also added to the additionplate, and finally 120 uL of HBSS/20 mM HEPES (for a total of 150 uL).Cells were then removed from the incubator and equilibrated to roomtemperature for 10 minutes, then 22.5 uL of 10× test compounds wereadded in triplicate to the plates and incubated at room temperature for10 minutes (Tropisetron was used as a positive control in every assay).Test plate and addition plate were loaded into the FlexStation III(Molecular Devices), and using the fluidics, 22.5 uL compound additionswere made (at t=˜17 seconds), and fluorescence was measured for 90seconds, reading every 2.2 seconds. Data sets were analyzed as max minusmin using Software Max Pro (Molecular Devices). IC₅₀ curves weregenerated using non-linear regression in GraphPad Prism.

Approximate IC₅₀ value of a representative number of compounds ofFormula (I) in this assay are provided in the Table 2 below.

TABLE 2 Cpd. No. from Table I IC50 Cpd. No. from IC50 Cpd. No. fromabove [nM] Table I above [nM] Table I above IC50 [nM] 1 0.95 2 0.51 30.96 4 0.69 5 0.62 6 1.1 7 2.86 8 0.81 9 0.68 10 0.65 11 0.60 12 0.882513 0.72 14 1.34 15 0.662 16 2.5 17 0.75 18 2.013 19 3.68 20 1.5 21 1.1022 0.65 23 1.01 25 1.39 26 1.20 27 1.44 28 2.04 29 0.462 30 0.74531 >1000 32 1.36In addition, in a head-to-head comparative study Compound 15 of Table 1,Example 5, had an IC50 of 3.48 in this assay, while the compound ofexample Reference 7 above had an IC50 in this assay of 89.1 nM.

Biological Example 2 Rodent Novel Object Recognition (NOR) Assay inPhencyclidine-Induced Cognitive Deficits Modeling Schizophrenia

The aim of this study is to investigate the ability of the compounds ofthe invention to improve subchronic PCP-induced impairment in cognitionmemory using the NOR task in the rat, a paradigm of relevance tocognition in schizophrenia. Adult male Sprague-Dawley rats (250-350 g;Harlan, USA) are used for the experiments Animal are acclimated to thefacility for 7 days prior to experimentation. Seven groups of 14 animalsper group are used for the experiment. One group of animals receivevehicle (0.9% saline twice daily) and the remaining six groups receivePCP (2.5 mg/kg, s.c. twice daily) for 7 days, followed by 5-days drugfree. On the test day, the animals are allowed to acclimate to thetesting room for 30 min prior to initiation of experiments. Experimentsare carried out in a white plexiglass chamber, designated as theexperimental arena. The arena is placed in a dark experimental room thatis illuminated by a halogen lamp, providing a dim light to the arena.

Animals are placed in the arena for a 5 minute period to freely explorethe test chamber in the absence of objects (habituation). Animals arethen returned to their home cage immediately upon completion ofhabituation for a 120 min period. The test compound (0.1, 1, 10 mg/kgs.c.), or vehicle (veh, saline) is administered 120 min prior to T1 andgalantamine (5 mg/kg, i.p.) is administered 30 min prior to T1. Animalsare returned to the arena which contained two identical objects (plasticballs) placed at one end of the arena (acquisition, T1), and allowed toexplore for a 5 min period. The time spent exploring the two objects isrecorded. Animals are once again returned to the home cage for a periodof 120 min (ITI).

ITI is followed by the retertion phase (T2) where one of the objectspresented in the first trial is replaced by a novel object and animalsare allowed to explore for an additional 5 min period. Again, the timespent exploring the two objects is recorded.

For the retertion phase, the differences between the time spentexploring the familiar object and the novel object are examined. Allsessions are recorded and scored blindly for the time exploring objects.Exploration is defined as touching the object or directing nose towardsobject at a distance less that 2 cm. A minimal exploration criterion isused such that only animals with exploration time of greater than 5seconds per object are included.

Comparisons of all treatment groups are conducted using a one-way ANOVAfollowed by a Bonferroni's post hoc test for multiple comparisons.

Biological Example 3 Nicotinic α-7 Receptor Binding Assay

The evaluation of binding at the nicotinic α-7 receptor was carried outat Eurofins Pharma Services. Compound 15 of Table 1, Example 5, had anIC50 in this assay of >10 μM while the compound of Reference 7 above hadan IC50 in this assay of 1.66 μM.

FORMULATION EXAMPLES

The following are representative pharmaceutical formulations containinga compound of Formula (I).

Tablet Formulation

The following ingredients are mixed intimately and pressed into singlescored tablets.

Ingredient Quantity per tablet compound of this invention 0.5-150 mgcornstarch 50 mg croscarmellose sodium 25 mg lactose 120 mg magnesiumstearate 5 mg

Capsule Formulation

The following ingredients are mixed intimately and loaded into ahard-shell gelatin capsule.

Ingredient Quantity per capsule compound of this invention 0.5-150 mglactose spray dried    148 mg magnesium stearate     2 mg InjectableFormulation

Compound of the invention (e.g., compound 1) in 2% HPMC, 1% Tween 80 inDI water, pH 2.2 with MSA, q.s. to at least 20 mg/mL.

What is claimed is:
 1. A compound of Formula (I):

wherein: Z is O or NR_(a) where R_(a) is hydrogen or C₁₋₆ alkyl; R₁ is aring of the formula (a)-(h) below:

R₂ is hydrogen, C₁₋₆ alkyl, or C₁₋₆ haloalkyl; each R₃ is independentlyhydrogen, C₁₋₆ alkyl, C₁₋₆ alkoxy, C₁₋₆ haloalkoxy, or halo and can bepresent on any carbon atom in the rings; R₄ is pyridinyl or pyrazolyleach optionally substituted with one or two substituents independentlyselected from C₁₋₆ alkyl, C₁₋₆ haloalkyl, C₁₋₆ haloalkoxy, C₁₋₆ alkoxy,cyano, or halo; all of X₁, X₂, X₃, and X₄ are CR₅ or one of X₁, X₂, X₃,and X₄ is N and the others are CR₅; each R₅ is independently hydrogen,C₁₋₆ alkyl, halo, hydroxy, or cyano provided that at least one of R₅ ishydrogen; X⁵ is N or CR⁶ where R⁶ is hydrogen, C₁₋₆ alkyl, or halo; or apharmaceutically acceptable salt thereof or N-oxide thereof.
 2. Thecompound or pharmaceutically acceptable salt of claim 1 wherein R¹ is aring of formula (a) or (d).
 3. The compound or pharmaceuticallyacceptable salt of claim 1 wherein R¹ is a ring of formula (e), (f), or(g).
 4. The compound or pharmaceutically acceptable salt of claim 1wherein R¹ is a ring of formula (e).
 5. The compound or pharmaceuticallyacceptable salt of claims 1-4 wherein each R³ is hydrogen.
 6. Thecompound or pharmaceutically acceptable salt of claims 1-4 wherein R² ishydrogen and each R³ is hydrogen.
 7. The compound or pharmaceuticallyacceptable salt of claims 1-4 wherein each R³ is independently hydrogenor methyl and R² is C₁₋₆ alkyl.
 8. The compound or pharmaceuticallyacceptable salt of claims 1-4 wherein R² is methyl and each R³ ishydrogen.
 9. The compound or pharmaceutically acceptable salt of claim 8wherein all of X₁, X₂, X₃, and X₄ are CR₅.
 10. The compound orpharmaceutically acceptable salt of claim 8 wherein all of X₁, X₂, X₃,and X₄ are CR₅ and each R₅ is hydrogen.
 11. The compound orpharmaceutically acceptable salt of claim 8 wherein one of X₁, X₂, X₃,and X₄ is N and the others are CR₅.
 12. The compound or pharmaceuticallyacceptable salt of claim 8 wherein X₁ is N and X₂, X₃, and X₄ are CR₅.13. A compound claim 1 selected from:(1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(pyridin-3-yl)-1H-indole-3-carboxylate;(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-(2-fluoroethyl)-1H-pyrazol-4-yl)-1H-indole-3-carboxylate;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-2-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-4-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-d₃-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-d₃-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-2-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide;5-fluoro-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-2-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide;5-fluoro-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-pyrrolo[2,3-b]pyridine-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(2-methylpyridin-3-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(4-methylpyridin-3-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-indole-3-carboxamide;1-(1-methyl-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,1-(1-methyl-1H-pyrazol-3-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,1-(1-methyl-1H-pyrazol-5-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide,N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)-1H-indole-3-carboxamide,1-(1-(difluoromethyl)-1H-pyrazol-4-yl)-N-((1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1H-indole-3-carboxamide;(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxylate;N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(pyridin-3-yl)-1H-indole-3-carboxamide;N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamide;(1R,5S,7S)-9-methyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl1-(1H-pyrazol-4-yl)-1H-indole-3-carboxylate;N-((1R,5S,7S)-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1H-pyrazol-4-yl)-1H-indole-3-carboxamide;andN-((1R,5S,7S)-9-ethyl-3-oxa-9-azabicyclo[3.3.1]nonan-7-yl)-1-(1-methyl-1H-pyrazol-4-yl)-1H-indole-3-carboxamide;or a pharmaceutically acceptable salt of each above mentioned compound.14. A pharmaceutical composition comprising a compound of claim 1 and apharmaceutically acceptable excipient.
 15. A method of treating adisease treatable by administration of a 5-HT3 receptor antagonistcomprising: administrating to a patient in need thereof atherapeutically effective amount of a compound of claim 1 or apharmaceutically acceptable salt thereof